A prospectus on kinetic heliophysics

Area of Science:

• Plasma Physics
• Heliophysics
• Astrophysics

Background:

• Heliospheric plasmas are characterized by low density and high temperatures.
• Macroscopic heliospheric evolution is significantly influenced by kinetic plasma physics.
• Fundamental microphysical mechanisms remain poorly understood.

Purpose of the Study:

• Investigate four grand-challenge problems in kinetic heliophysics: kinetic turbulence, collisionless magnetic reconnection, particle acceleration, and kinetic instabilities.
• Explore the potential of high-resolution spacecraft measurements and advanced simulations to advance understanding.
• Examine key considerations for future research in kinetic heliophysics.

Main Methods:

• Utilizing high cadence and phase-space resolution particle velocity distribution measurements from spacecraft.
• Employing massively parallel nonlinear kinetic simulations of weakly collisional plasmas.
• Analyzing high-dimensional (3D-3V) phase space data through physics-based reductions.

Main Results:

• Turbulent dissipation followed by particle heating is identified as a two-step process in weakly collisional plasmas.
• Innovative analysis methods, like the field-particle correlation technique, are crucial for deeper insights.
• Connecting microscale kinetic physics with macroscale heliospheric evolution is essential.

Conclusions:

• Full utilization of particle velocity distribution information is key to transforming understanding of kinetic mechanisms.
• Addressing the big-data challenge in visualizing high-dimensional phase space is critical.
• A systems approach linking kinetic physics to heliospheric evolution will drive future advancements in the field.